This invention relates to new and useful improvements in saw chain grinding machines.
Saw chains now in use have right and left cutter elements on alternate cutter links. A common cutter element comprises the chisel-bit type chain. This cutter element has an L-shaped cutting edge with a working corner that severs the crossgrain. A chisel edge leads rearwardly from this cutting edge at a selected angle. This angle preferably is of selected degree depending on the type of wood being cut, namely, the softer the wood the steeper the angle of this edge. Prior devices, such as shown in U.S. Pat. No. Re. 28057 are known which have structure that varies the relative angle between the axis of the chain support and the axis of the grinding wheel. This is done by adjusting the angle of tilt of the motor and grinder assembly. When this is done, still other adjustments are required to bring the cutter elements back into the correct position to be ground. These further adjustments are required since the pivot of the motor and grinding wheel assembly is not at the grinding point.
The oppositely directed cutter elements of saw chains require grinding from opposite directions, and if a smooth and fast cut is desired, the right and left cutter elements must all be ground uniformly. Prior devices have been conceived that seek uniform engagement of the opposite cutter elements with the grinding wheel as by symmetrical side holders for the chain or swinging arm mechanisms. Another device for uniform grinding is shown in my U.S. Pat. No. 4,836,058, wherein pivotal support means for a chain holder is provided that is parallel with the plane of the grinding wheel. This structure facilitates grinding of the oppositely facing cutter elements at the same radial point of grind on the edge of the grinding wheel, whereby by simply pivoting the holder between identical opposite angular directions, symmetrical sharpening of opposite cutter elements is accomplished without transferring the chain from one side of the wheel to the other.